Particular embodiments generally relate to current estimation.
Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
The use of electronic devices is popular in stationary and mobile environments. One kind of visual display is typically used in both environments. For example, the same kind of visual display is used in electronic devices from large sign/advertising boards to cellular phones or portable game players. Energy consumption is a concern in the design of the electronic devices. For example, in the marketplace, an electronic device that uses less energy may take significant precedence over other devices.
Light-emitting diodes (LEDs) are being used in displays because of the LEDs' energy efficiency, reliability, low maintenance, and environmental friendliness. LEDs have been used in various devices, such as signal devices (e.g. traffic lights, exit signs, and signboards) as well as in some illumination devices, such as flashlights. Additionally, LEDs may be used in light sources for general illumination in homes to commercial applications. LEDs have many advantages, such as long life, energy savings, better quality light output, safety, size, and durability.
A single-stage flyback solution for driving LEDs is used because of the flyback solution's simplicity and cost reduction. The flyback solution requires that a current be detected on the secondary side of a transformer of the flyback solution. This increases the amount of components in the implementation, such as output components, secondary constant current control circuits, and an optocoupler are needed on the secondary side. These components are used to detect the current on the secondary side and then send the current value back to the primary side. The detected current is used by the primary side to adjust an on and off time of a switch in the flyback solution.